![]() In aberrated eyes, however, contrast decreases with pupillary dilation because of the impact of aberrations on the retinal point spread function (Figure 1). ![]() In eyes with no HOAs, retinal image quality increases proportionately to pupillary diameter owing to increases in the diffraction bandwidth. UNDERLYING FACTORSįor a well-focused eye (defocus = 0 D), the optical impact of pupillary diameter is modulated by the competing negative effects of diffraction with smaller pupils and the blur generated by optical aberrations with larger pupils. This article attempts to provide a framework that will help eye care practitioners to understand pupillary modulation more fully and evaluate the benefits and compromises involved in pupillary modulation during a person’s typical day. The pupillary diameter to optimize distance, intermediate, or near vision can differ because it is affected by a number of determining factors, including retinal illuminance, diffraction, lower-order aberrations (LOAs ie, defocus), and higher-order aberrations (HOAs) Studies of visual performance when the entrance pupil is artificially modified by viewing through small apertures speak directly to the original query: What is the optimal pupil size? As this article explains, the answer to this question is that it depends. Psychophysical studies suggest that, for a well-focused eye, pupil size iterates to whatever achieves the best visual acuity, 1 grating detection, 2 and retinal image quality 3 for viewing objects at various levels of environmental light. This new approach to presbyopia was heralded by the recent first-in-class FDA approval of Vuity (pilocarpine HCl ophthalmic solution 1.25%, Allergan) and affirmative decision on the premarket approval application for the IC-8 small-aperture IOL (AcuFocus), both for the treatment of presbyopia.Ĭhanges in pupillary diameter are highly dynamic they are influenced by accommodative effort, lighting, refractive error, emotional state, age, and other factors. Today, the subject has practical implications given the number of pupil-modulating drops and small-aperture IOLs in development to treat presbyopia. Considerations of optimal pupil size used to be a largely intellectual exercise. ![]()
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